The recent interesting nucleic acide in plasma and serum has opened upNumerous new areas of investigation and new possibilities forMolecular diagnosis in oncology increased amounts of circulating DNAHave been found in a variety of disorders including canceraute immuneDiseases , diabetic complications and infection .Studies showed that there is an increasing level of circulating tumorRelated DNA related to higher stages of disease and these finding haveImportant implication for detection , monitoring and prognosis of manyTypes of malgnacies .Discovery of fetal DNA in maternal plasma has opened up newPossibilities for non invasive prenatal diagnosis and monitoringQuantitative aberration and a number of pregnancy associated disorders.An evolution in molecular techniques has recently allowed much betterCharacterization of circulating in these conditions and led to theEmergence of a new field of investigations Recent discoveries haveBrought anew understanding of circulating DNA and show promise forThe detdction and follow up of various disorders.